1. Field of the Invention
This invention relates to a single-reel type tape cartridge for magnetic recording-reproducing apparatus.
2. Prior Art
Japanese Patent Application Kokai No. 63-251983 discloses a single-reel type tape cartridge in which a brake lock is urged downward by a spring member to keep teeth formed on the brake lock in mesh with teeth of the reel so as to avoid unwanted turning of the reel when the tape cartridge is not in use. When the cartridge is loaded in recording-reproducing apparatus (hereinafter called a "recorder"), a projection of the brake lock is raised by a drive of the recorder to a predetermined position where the teeth of the reel and the brake lock are out of mesh to set the reel free to turn and allow the tape to be drawn out. The brake lock is formed with a cruciform recess adapted to engage with a cruciform projection in the upper casing of the housing, whereby the brake lock is made movable upward and downward without turning.
FIG. 4 is an exploded view of a single-reel type cartridge of the prior art, and FIG. 5 is a cross sectional view of the essential parts of the cartridge. For a better understanding of the arrangement the components are shown upside down. The cartridge comprises a housing composed of an upper casing 1 and a lower casing 2, and a single tape reel 3 around which a length of tape 14 is wound and which is turnably held within the housing.
Between upper and lower casings 1, 2 is formed an opening composed of half openings 12, 22 in the both casings and which is adapted to receive a leader block 18 as the latter is drawn out by a drive member of a recorder.
Tape reel 3 has a hub 32 formed in one piece with a lower flange 33. Tape reel 3 is driven for rotation by a drive of a recorder through the opening 22 of lower casing 2.
On the inner surface of hub 32 is provided teeth adapted to engage with a brake lock 5 to prevent unwanted turning of tape reel 3 when the cartridge is not in use.
Brake lock 5 has teeth 51 on its underside which is in mesh with the teeth of hub 32. Brake lock 5 is normally urged in a braking position by a brake spring 4.
Follower projections 52 of brake lock 5 are formed with recesses 73 for sliding engagement with a guide member 13 formed on the inner surface of upper casing 1, so that brake lock 5 can be positively moved up and down between a lower braking position and an upper brake release position.
A brake-releasing projection 63, formed on the underside of brake lock 5, fits in a center hole 43 at the bottom of hub 32. As the cartridge is inserted in a recorder, brake-releasing projection 63 is forced upward, with concomitant upward movement of brake lock 5 out of engagement with tape reel 3, setting the reel free to turn.
The beginning of tape 14 is wound round a pin member 8, which in turn is fitted securely in a pin-receiving groove of leader block 18. When the cartridge is loaded in a recorder, a draw-out member of the recorder enters a clamp groove 19 of leader block 18 to grip the block, draw it out, thread the tape up to take-up reel along a tape path inside the recorder, and eventually hold the block in a recess formed on the outer periphery of the take-up reel in the recorder.
Not merely the counterpart of the tape cartridge of the prior art but generally the brake mechanism of the character in which a brake lock moves upward and downward as fitted in a projection of projections formed in the upper casing of a cartridge housing has a construction such that a guide member (indicated at 11 in FIGS. 1 and 2) of the upper casing and recesses of the brake lock are combined so as to avoid turning of the brake lock itself. Usually a tape cartridge is assembled by first packing the lower casing with upper casing. The assembling is impossible if the recesses of the brake lock and the projections of the upper casing are not properly aligned, and actually the aligning has involved much difficulty.